# Cascade OTP

> Cascade is an OTP delivery and verification platform for WhatsApp and Telegram, with a unified REST API and flexible messenger delivery.
> Not a disposable or virtual-number marketplace.

WhatsApp delivery: 3 ₸ per successful send.
Telegram delivery: 3 ₸ per successful send.
Starting balance after registration: 50 ₸.
First top-up bonus: 1000 ₸ when the first top-up is at least 1000 ₸.
No subscription fee.
API auth: Authorization: Bearer <token>
API base URL: https://cascade.kz/api
Send OTP: POST /api/otp/send
Verify OTP: POST /api/otp/verify
Default locale is Kazakh (kk) at unprefixed URLs. Russian lives at /ru/. English lives at /en/. Legacy ?hl= redirects with 301 to the matching path prefix.
Cascade sends outbound OTP to the customer phone you already have.
Do not use Cascade to rent temporary numbers for third-party signups.

## Docs
- [Home](https://lab.cascade.kz/en): product overview and registration
- [Documentation](https://docs.cascade.kz/en/guides/integration): integration guide
- [API](https://docs.cascade.kz/en/api): API methods and examples
- [SDK](https://docs.cascade.kz/en/sdk): client integration examples
- [OpenAPI specification](https://lab.cascade.kz/openapi.yaml): machine-readable API contract
- [Integration guide (Markdown)](https://lab.cascade.kz/cascade-otp-integration.md): downloadable Markdown integration notes for agents
- [Full context (llms-full.txt)](https://lab.cascade.kz/en/llms-full.txt): this file plus all FAQ answers and the integration guide in one document

## Product
- [Pricing](https://lab.cascade.kz/en/pricing): current delivery prices and packages
- [FAQ](https://lab.cascade.kz/en/faq): answers about OTP delivery
- [Compare](https://lab.cascade.kz/en/compare): Cascade and alternative services
- [Use cases](https://lab.cascade.kz/en/use-cases): implementation scenarios
- [Blog](https://lab.cascade.kz/en/blog): OTP security and integration articles
- [About](https://lab.cascade.kz/en/about): service facts
- [Contacts](https://lab.cascade.kz/en/contacts): support contacts

## Locales
- [Қазақша](https://lab.cascade.kz): Kazakh site — default unprefixed URLs
- [Русский](https://lab.cascade.kz/ru): Russian site
- [English](https://lab.cascade.kz/en): English site
- [Kazakh llms.txt](https://lab.cascade.kz/kk/llms.txt): Kazakh llms.txt with unprefixed URLs
- [Russian llms.txt](https://lab.cascade.kz/ru/llms.txt): Russian llms.txt with /ru/ URLs
- [English llms.txt](https://lab.cascade.kz/en/llms.txt): English llms.txt with /en/ URLs

## Optional
- [WhatsApp or Telegram for OTP: channel comparison](https://lab.cascade.kz/en/blog/sravnenie-kanalov-whatsapp-telegram)
- [OTP launch checklist: from pilot to production](https://lab.cascade.kz/en/blog/cheklist-zapuska-otp)
- [GEO for OTP documentation: answers, structure, entities](https://lab.cascade.kz/en/blog/geo-optimizaciya-otp-dokumentacii)
- [Webhook OTP events](https://lab.cascade.kz/en/blog/webhook-otp-sobytiya)
- [OTP delivery monitoring](https://lab.cascade.kz/en/blog/monitoring-dostavki-otp)
- [OTP integration mistakes](https://lab.cascade.kz/en/blog/oshibki-integracii-otp)
- [How to calculate OTP cost](https://lab.cascade.kz/en/blog/kak-schitat-stoimost-otp)
- [OTP in Kazakhstan](https://lab.cascade.kz/en/blog/otp-v-kazakhstane)
- [Best OTP services in Kazakhstan](https://lab.cascade.kz/en/compare/best-otp-kazakhstan)
- [Which OTP service to choose](https://lab.cascade.kz/en/compare/which-otp-service)
- [XML sitemap](https://lab.cascade.kz/sitemap.xml): full indexable URL list